alpha-Difluoromethylornithine (DFMO; RMI 71,782) given in drinking water in concentrations as low as 0.0625% inhibited infections of Eimeria tenella and minimized the development of lesions in chickens. It had approximately the same activity as a currently used anticoccidial drug, amprolium, and also had the advantage of being relatively nontoxic in chickens. Body weight gains were not reduced in chickens given 0.0635% DFMO or less for 14 days starting 8 days before they were inoculated with oocysts, but were reduced in chickens given drinking water containing 0.125 and 0.25% DFMO. The anticoccidial activity of DFMO was completely reversed by injection (intraabdominal) of putrescine hydrochloride (300 mg/kg of body weight/day), indicating that the drug may act by blocking putrescine biosynthesis. Inoculated chickens, in which coccidial lesion development was suppressed by DFMO, resisted subsequent challenge exposure with E tenella, as did nontreated infected control birds which had recovered from infection.
The corona penetrating enzyme of sperm is shown to be esterolytic in nature. This is the first known function of the several sperm esterases and indicates the cementing substance between cells of the corona radiata contains an essential ester linkage.